Visualization of extradural blood patch for post lumbar puncture headache by magnetic resonance imaging

We describe a case of post lumbar puncture headache treated by extradural blood patch. Magnetic resonance imaging (MRI) demonstrated a large extradural haematoma extending over four spinal segments and extending out through the neural outlet foramina. There was significant compression of the thecal sac, supporting the theory that extradural blood patch causes tamponade at the site of dural puncture. The spread of clot was predominantly upwards from the injection site and subarachnoid extension of blood was also demonstrated.